A Quartile graph, a diagram displaying the distribution of one-dimensional data, can directly show the distribution pattern of data, including five data points: lowest quartile, first quartile, median quartile, third quartile and highest quartile. The lowest quartile and the highest quartile refer to the minimum value and the maximum value respectively, the first quartile means that 25% of all the data is less than the value corresponding to the first quartile, similarly, the median quartile means that 50% of all the data is less than the value corresponding to the median quartile, and the third quartile means that 75% of all the data is less than the value corresponding to the third quartile. The quartile graph is only a tool for displaying, and only for displaying the distribution of one-dimensional data. Hence there lacks a visualization method for displaying the distribution of two-dimensional data by using a quartile graph.